Exponential Decay (Half-Life) $A_t=A_0(\frac{1}{2})^\frac{t}{h}$

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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A radioactive substance has a half-life of 3 hours. If you start with 100 g, what mass will remain after 12 hours?

(Note: This lesson includes a brief explanation of half-life.)

2

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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A radioactive substance has a half-life of 18 hours. If you start with 18 g, what mass will remain after 3 days?

3

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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A radioactive substance has a half-life of 15 hours. If you start with 100 kg, what mass will remain after 2 days?

4

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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A radioactive substance has a half-life of 20 hours. How long will it take for 400g to decay to 50g?

5

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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A radioactive substance has a half-life of 7 hours. How long will it take for 768g to decay to 24g?

6

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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A radioactive substance has a half-life of 5 days. How long will it take for 1312 kg to decay to 82 kg?

7

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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If you have 68g of a radioactive substance that decays to 17g after 12 days, what is the half-life?

8

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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If you have 192g of a radioactive substance that decays to 3g after 18 years, what is the half-life?

9

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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A radioactive substance decays to $\frac{1}{16}$ of its original amount after 24 days. What is the half-life?
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Good test question!

10

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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A radioactive substance decays to $\frac{1}{32}$ of its original amount after 15 days. What is the half-life?
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11

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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How long will it take for a radioactive substance to decay to $\frac{1}{4}$ of its original amount, if the half-life is 40 minutes?

12

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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How long will it take for a radioactive substance to decay to 25% of its original amount, if the half-life is 5 days?
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Good test question!

13

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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How long will it take for a radioactive substance to decay to 12.5% of its original amount, if the half-life is 9 days?

14

Use the equation $A_t=A_0(\frac{1}{2})^\frac{t}{h}$ to solve.
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What is the half-life of a radioactive substance if it decays to 6.25% of its original amount after 32 minutes?